Spaceflight Insider

Soyuz 2.1b launches military satellite into orbit

Tomasz Nowakowski

December 2nd, 2017

Archive photo of a Soyuz-2.1b launch from Plesetsk Cosmodrome (2016-02-07). Photo Credit: Ministry of Defence of the Russian Federation

The recent failure of a Soyuz 2.1b mission, which was unable to place a fleet of 19 satellites into their targeted orbits, has not stopped Russia from sending another such booster into space. This time, lifting off from the Plesetsk Cosmodrome at 10:43 GMT (5:43 a.m. EST) on Saturday, December 2, 2017, a Soyuz 2.1b successfully orbited the Lotos-S1 (№ 803) military spacecraft for the Russian Defense Ministry.

Although the failure of last Tuesday’s Soyuz 2.1b mission that was tasked with launching the Meteor-M 2-1 Earth-observing spacecraft and 18 smaller payloads is still being investigated by a space accident commission, Roscosmos decided to go ahead with its launch schedule that was already previously approved.

Initial reports revealed that the satellites may have been lost due to a failure in the GLONASS equipment on board the rocket that had lifted off from the Vostochny Cosmodrome on Tuesday. Consequently, the Fregat-M upper stage was not able to inject the payload into the desired orbit. As for today’s launch, the Soyuz 2.1b flew without a Fregat-M, which avoided having a repeat occurrence of the suspected malfunction.

Today’s mission was initially planned to take place on October 25 but was postponed to mid-November and then, once again, to December 2, due to problems with the payload.

The launch

On Saturday, the Soyuz 2.1b rocket thundered off the launch pad powered by its RD-107A engines, signaling the start of its short vertical climb. The four boosters responsible for accelerating the launch vehicle during the initial phase of the flight were jettisoned at approximately two minutes after the rocket had lifted off of the launch pad far below.

The Soyuz launch vehicle continued the ascent being powered by its core stage until it too detached at about four-and-a-half minutes into the flight. Afterward, the third stage took control over the mission for about four minutes until it ended with the insertion of the payload into orbit.

Saturday’s launch and flight were controlled by a ground-based automatic control system, with the commander of Russia’s Aerospace Defense Forces, Lt. Gen. Alexander Golovko, in charge of flight of the rocket with its precious cargo.

“The Soyuz 2.1b carrier at the designated time took successfully to the target orbit the space apparatus for interests of the Russian Defense Ministry,” the state-run TASS press agency reported about half an hour after the launch.

The mission’s sole passenger was the Lotos-S1 electronic signals intelligence (ELINT) satellite. The spacecraft is based on the Yantar bus and features two deployable solar arrays. After injection into orbit, the satellite received the official designation Kosmos 2524.

Lotos satellites belong to Russia’s Liana program, which aims to modernize the country’s signals intelligence (SIGINT) capabilities. Lotos network replaces the former Tselina series of satellites, launched between 1967 and 2007. The first prototype Lotos satellite, designated Lotos-S, was sent to orbit in November of 2009.

The Soyuz 2.1b rocket

The Soyuz 2.1b rocket employed for this Saturday’s launch is an upgraded version of the three-stage Soyuz 2 booster. The 151-foot (46.1-meter) tall launch vehicle has a total mass of some 672,000 pounds (304,814 kilograms) and is designed to put satellites into a variety of orbits.

The booster is capable of putting up to 18,100 pounds (8,210 kilograms) into low-Earth orbit (LEO), 10,800 pounds (4,899 kilograms) into a Sun-synchronous orbit (SSO), and 7,170 pounds (3,252 kilograms) into a geostationary transfer orbit (GTO). The first launch of this version of the rocket took place from Plesetsk on July 26, 2008, with a classified military payload.

As noted, the Soyuz 2.1b rocket uses four RD-107A engines at liftoff, which burn for about two minutes. The first stage, which measures about 88.9 feet (27.1 meters) long and 9.7 feet (2.95 meters) in diameter, is equipped with a lone RD-108A engine. The rocket’s second stage has a length of 22 feet (6.7 meters) and is 8.7 feet (2.66 meters) in diameter. The 2.1b version of Soyuz has an upgraded RD-0124 engine with a second stage that has improved performance over previous iterations of the design.

For some launches, the Soyuz 2.1b rocket is used in a configuration with a Fregat-M third stage. This upper stage measures approximately 4.9 feet (1.5 meters) long and is 11 feet (3.35 meters) in diameter. Its S5.92 engine is designed to burn for a period of about 18 minutes.

Fregat-M is responsible for the orbital insertion of the satellite. However, it can also be used as an ‘escape stage’ to send probes on interplanetary trajectories. Fregat stages are currently used as the fourth stage for some Soyuz-FG launch vehicles as well.

Saturday’s launch was the 18th flight for Russia and the fourth launch from Plesetsk in 2017. The next scheduled mission of a Russian booster is currently slated for Dec. 17 when a Soyuz-FG is planned to send the Soyuz MS-07 spacecraft with three members of the Expedition 54 crew to the International Space Station (ISS).

Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.